http://www.popularmechanics.com/technology/robots/news/a22903/rov-sea-drones/#
The next drone revolution is happening underwater. Just as flying drones have changed from expensive specialist tools to mass-market million-sellers in a few short years, their aquatic counterparts are opening up the seas.
Unmanned submarines, known as Remotely Operated Vehicles, can regularly be seen on television exploring sunken cities or looking for crashed aircraft. They are connected to a mothership via a tether and can dive deeper and longer than a SCUBA diver. The advantages are obvious: For humans, anything below a hundred feet is a “deep dive” that can require hours of decompression. Not so for bots, which can swim deeper and faster.
ROVs can handle conditions that are unsafe for human divers, like swimming in oil, sewage, and extreme cold. They do not get hungry or tired, and a serious accident is an irritation rather than a disaster. Some modern ROVs are small enough to carry around easily and transport by air, unlike diving equipment. The equipment for a technical diver – one who dives below a hundred feet — weighs at least two hundred pounds.
The problem is that ROVs are expensive because they are built from custom electronics. The 20-lb. GNOM Standard-01 ROV used in industry will run you about 10 grand, and that is the budget end of the market. The revolution is coming from enthusiasts taking an open-source approach, using off-the-shelf hardware and a little innovation to build low-cost, easy-to-use underwater vehicles.
One of the first in this field was OpenROV, a group that uses Linux computers andKickstarter funding to develop their submersibles. Led by NASA engineer Eric Stackpole, the group launched a 5 lb. consumer/educational ROV the size of a laptop in kit form for just $900 in 2012. Their latest model, shipping in November, is the Trident. This sub is small enough to fit in a rucksack under an airplane seat. Trident’s tether connects to a floating, towed buoy with a Wi-Fi connection to the operator, giving a new level of freedom.
Another startup, Blue Robotics, aims to provide the capabilities of an industrial ROV at a fraction of the cost. Its BlueROV2, launched last month, is a 20-lb. craft that can send back high-definition video from 300 feet down, aided by a couple of 1500 lumen headlights (it gets dark down there). You can buy BlueROV2 for around $3,000, depending on options.
Some of components of BlueROV2 are familiar, like the Raspberry Pi processor and a Pixhawk autopilot commonly used for drones. But founder Rustom Jehangir says that not everything was available off the shelf, so they needed to do some developing, particularly in the area of thrusters.
“The electronics and software can be carried over from the drone world, but most of the vehicle parts cannot,” Jenagir told Popular Mechanics. “That is what we built our company to address. Our primary goal is to build low-cost enabling parts like thrusters, enclosures, sensors, and just about everything else needed to kickstart this industry.”
Existing thrusters have brushes for electrical contact. That means seals, metal bearings, and oil and grease that require frequent maintenance. With the aid of a crowdfunding campaign, Jehangir developed a low-cost brushless thruster. It is a sealed unit that requires no maintenance.
Cheap sonar, acoustic communication and other sensors will all help transform the underwater drone business, and these are all in the pipeline. The effect is likely to be a steady stream of affordable miniature submarines for industry and for consumers over the next few years. “The drone industry exploded when low-cost electronics hardware and open-source software became available,” Jehangir says.
The BlueROV2 is first being made available in kit form, with shipping commencing last month. Jehangir says this will ensure that early users are knowledgeable enthusiasts, a community which is great at providing feedback. When the ready-assembled version is produced early next year, it will be easy enough for an inexperienced operator to use out of the box.
Just as drones opened up aerial photography for researchers, farmers, and filmmakers who could never have afforded it before, the new generation of ROVs are likely to attract interest from new users. Many of these will be academic, in particular in the field of marine biology and archaeology. For example, students from CSU Monterey Bay have been using a BlueROV2 prototype to film reefs on the small south Pacific island of Ulithi. These are comparatively untouched reefs, and the ROV provides an easy means of accessing it.
Meanwhile, archaeologists from Long Beach College are using another prototype to find freshwater springs underwater off Catalina Island in California. Such springs are often associated with ancient settlements submerged by the rising sea, so springs may help locate traces of prehistoric human occupation.
The biggest application will be in aquaculture. While the offshore oil and gas industries have always had the money for ROVs, fish farmers work on a much tighter budget. A new generation of low-cost ROVs should give the industry greatly improved capability for monitoring beds of shellfish, fish populations, anchors and underwater infrastructure. Blue Robotics are already working with Catalina Sea Ranch which grows mussels, as well as farms in Ensenada, Mexico.
While the ROV market may not spawn million-sellers like the DJI Phantom drone did for flying drones, it is likely to attract plenty of business interest, and more than a few hobbyists and students. Some, like the OpenROV team, may be initially motivated by the lure of sunken treasure, and then get hooked on underwater exploration. Because, while aerial drones see things you have seen before from another angle, underwater ROVs can open up a whole new world.
Robotic Technology in Water and Air 